Reducing the cost of offshore platform construction is an urgent issue for marginal oilfield development.The offshore oil well structure includes a riser and a surface casing.The riser,surface casing and oil well ceme...Reducing the cost of offshore platform construction is an urgent issue for marginal oilfield development.The offshore oil well structure includes a riser and a surface casing.The riser,surface casing and oil well cement can be considered special variable cross-section piles.Replacing or partially replacing the steel pipe pile foundation with a variable cross-section pile to provide the required bearing capacity for an offshore oil platform can reduce the cost of foundation construction and improve the economic efficiency of production.In this paper,the finite element analysis method is used to investigate the variable cross-section bearing mode of composite piles composed of a riser and a surface casing in saturated clay under a vertical load.The calculation formula of the bearing capacity at the variable section is derived based on the theory of spherical cavity expansion,the influencing factors of the bearing capacity coefficient N_(c) are revealed,and the calculation method of N_(c) is proposed.By comparing the calculation results with the results of the centrifuge test,the accuracy and applicability of the calculation method are verified.The results show that the riser composite pile has a rigid core in the soil under the variable cross-section,which increases the bearing capacity at the variable cross-section.展开更多
BACKGROUND A rectal neuroendocrine tumor(rNET)is a malignant tumor originating from neuroendocrine cells.Currently,tumor size is the primary basis for assessing tumor risk.CASE SUMMARY This article reports the case of...BACKGROUND A rectal neuroendocrine tumor(rNET)is a malignant tumor originating from neuroendocrine cells.Currently,tumor size is the primary basis for assessing tumor risk.CASE SUMMARY This article reports the case of a 46-year-old male patient who underwent a colonoscopy that found a 3 mm rectal polypoid bulge.The pathological examination of a sample collected with biopsy forceps revealed a neuroendocrine tumor.Further endoscopic submucosal dissection rescue therapy was used.The presence of lymphatic vessels indicated that the tumor had infiltrated the negative resection margin.The lesion was located in the distal rectum near the anal canal.Therefore,to ensure the patient’s quality of life,follow-up observation was conducted after full communication with the patient.No tumor recurrence or distant metastasis has been found during the 13-mo follow-up after surgery.CONCLUSION Despite the presence of lymphatic invasion and extremely small diameter rNETs in our case,this phenomenon may not imply a higher risk of distant lymph node and organ metastasis.展开更多
Two new size factors of cross-section hollow coefficient and bending degree are introduced to reveal the size effect of bending forming of bimetallic composite tube.Hollow coefficient and bending degree can limit the ...Two new size factors of cross-section hollow coefficient and bending degree are introduced to reveal the size effect of bending forming of bimetallic composite tube.Hollow coefficient and bending degree can limit the commonly used bent tube to the size description range of(0,2.00).The evolution laws of the cross-section distortion forms in the hollow coefficient-bending degree interval are revealed as well as the action of the mandrel-cores on the size effect.Results show the mandrel-cores filling can expand the forming limit of the bent tube,but also bring two other forming defects of wrinkle and rupture.The identification factor(hollow coefficient multiply bending degree)provides a method for querying the cross-section distortion forms of all composite bending tubes.In the identification factor interval(0,1.00),the distribution area of bending forming defects of the composite tube is continuous.The thin-walled composite bending tube collapses when identification factor in(0,0.39),wrinkles when identification factor in[0.39,0.50),and ruptures when identification factor in[0.50,1.00).The mathematical model of size effect is derived,by which the average cross-section distortion rate is found to distribute like a radial leaf in the hollow coefficient-bending degree qualified forming space.The best forming zone is hollow coefficient 0.46-0.68,and bending degree 0.25-0.47.展开更多
BACKGROUND The common computed tomography findings of pulmonary Langerhans cell histiocytosis (PLCH) are multiple cysts and micronodules predominantly in middle to upper lung lobes.Non-cystic nodules and large nodules...BACKGROUND The common computed tomography findings of pulmonary Langerhans cell histiocytosis (PLCH) are multiple cysts and micronodules predominantly in middle to upper lung lobes.Non-cystic nodules and large nodules are atypical findings of PLCH.CASE SUMMARY The patient was a 48-year-old Japanese man with a smoking history (20 cigarettes/d,28 years) and no symptoms.Multiple nodules existed in all lung lobes,predominantly in the right lower lobe.Some nodules seemed to be distributed randomly,and others were adjacent to bronchus.Most nodules were solid;some small ones were cystic.The largest nodule was 22 mm in diameter.Although metastatic lung tumors were suspected,thoracoscopic lung biopsy led to the diagnosis of PLCH.At 6 months after he quit smoking,all nodules had almost disappeared.We investigated the characteristics of nodules at diagnosis in detail.Of 349 nodules in total,116 were in upper and 199 were in lower lobes.Ninety-six (27.5%) were cystic;the remaining 253 (72.5%) were non-cystic.The prevalence of cystic nodules was higher in upper lobes than in lower lobes (right upper 37.5% vs lower 18.2%,P = 0.0068;left upper 48.1% vs lower 24.4%,P = 0.0078).The average size (dia.) of cystic nodules was smaller than that of noncystic nodules (5.03 mm vs 7.40 mm,respectively,P < 0.0001).CONCLUSION Although multiple non-cystic nodules including large nodules (over 20 mm) are atypical,PLCH should be included in differential diagnoses.The presence of small cystic nodules predominantly in upper lobes and asymptomatic situation are also important for differential diagnoses to distinguish from metastatic cancers.展开更多
Randomized controlled trials(RCTs) are the gold standard in terms of study design, however, in the surgical setting conducting RCTs can often be unethical or logistically impossible. Case-control studies should become...Randomized controlled trials(RCTs) are the gold standard in terms of study design, however, in the surgical setting conducting RCTs can often be unethical or logistically impossible. Case-control studies should become the major study design used in surgical research when RCTs are unable to be conducted and definitely replacing case series which offer little insight into surgical outcomes and disease processes.展开更多
基金This research was financially supported by the National Science Fund for Distinguished Young Scholars(Grant No.51825904)the National Science and Technology Major Project from the Ministry of Science and Technology(MOST)of China(Grant No.2016ZX05058004-005).
文摘Reducing the cost of offshore platform construction is an urgent issue for marginal oilfield development.The offshore oil well structure includes a riser and a surface casing.The riser,surface casing and oil well cement can be considered special variable cross-section piles.Replacing or partially replacing the steel pipe pile foundation with a variable cross-section pile to provide the required bearing capacity for an offshore oil platform can reduce the cost of foundation construction and improve the economic efficiency of production.In this paper,the finite element analysis method is used to investigate the variable cross-section bearing mode of composite piles composed of a riser and a surface casing in saturated clay under a vertical load.The calculation formula of the bearing capacity at the variable section is derived based on the theory of spherical cavity expansion,the influencing factors of the bearing capacity coefficient N_(c) are revealed,and the calculation method of N_(c) is proposed.By comparing the calculation results with the results of the centrifuge test,the accuracy and applicability of the calculation method are verified.The results show that the riser composite pile has a rigid core in the soil under the variable cross-section,which increases the bearing capacity at the variable cross-section.
基金Supported by Guizhou Science and Technology Plan Project,No.ZK2022-General-443Science and Technology Fund of Guizhou Provincial Health and Health Commission,No.gzwkj2023-135。
文摘BACKGROUND A rectal neuroendocrine tumor(rNET)is a malignant tumor originating from neuroendocrine cells.Currently,tumor size is the primary basis for assessing tumor risk.CASE SUMMARY This article reports the case of a 46-year-old male patient who underwent a colonoscopy that found a 3 mm rectal polypoid bulge.The pathological examination of a sample collected with biopsy forceps revealed a neuroendocrine tumor.Further endoscopic submucosal dissection rescue therapy was used.The presence of lymphatic vessels indicated that the tumor had infiltrated the negative resection margin.The lesion was located in the distal rectum near the anal canal.Therefore,to ensure the patient’s quality of life,follow-up observation was conducted after full communication with the patient.No tumor recurrence or distant metastasis has been found during the 13-mo follow-up after surgery.CONCLUSION Despite the presence of lymphatic invasion and extremely small diameter rNETs in our case,this phenomenon may not imply a higher risk of distant lymph node and organ metastasis.
基金co-supported by the National Natural Science Foundation of China(Nos.51601070 and 51875263)the Open Project of Guangdong Key Laboratory of Precision Equipment and Manufacturing Technology,China(No.PEMT202102)the Natural Science Foundation of Jiangsu Province,China(No.BK20181447)。
文摘Two new size factors of cross-section hollow coefficient and bending degree are introduced to reveal the size effect of bending forming of bimetallic composite tube.Hollow coefficient and bending degree can limit the commonly used bent tube to the size description range of(0,2.00).The evolution laws of the cross-section distortion forms in the hollow coefficient-bending degree interval are revealed as well as the action of the mandrel-cores on the size effect.Results show the mandrel-cores filling can expand the forming limit of the bent tube,but also bring two other forming defects of wrinkle and rupture.The identification factor(hollow coefficient multiply bending degree)provides a method for querying the cross-section distortion forms of all composite bending tubes.In the identification factor interval(0,1.00),the distribution area of bending forming defects of the composite tube is continuous.The thin-walled composite bending tube collapses when identification factor in(0,0.39),wrinkles when identification factor in[0.39,0.50),and ruptures when identification factor in[0.50,1.00).The mathematical model of size effect is derived,by which the average cross-section distortion rate is found to distribute like a radial leaf in the hollow coefficient-bending degree qualified forming space.The best forming zone is hollow coefficient 0.46-0.68,and bending degree 0.25-0.47.
文摘BACKGROUND The common computed tomography findings of pulmonary Langerhans cell histiocytosis (PLCH) are multiple cysts and micronodules predominantly in middle to upper lung lobes.Non-cystic nodules and large nodules are atypical findings of PLCH.CASE SUMMARY The patient was a 48-year-old Japanese man with a smoking history (20 cigarettes/d,28 years) and no symptoms.Multiple nodules existed in all lung lobes,predominantly in the right lower lobe.Some nodules seemed to be distributed randomly,and others were adjacent to bronchus.Most nodules were solid;some small ones were cystic.The largest nodule was 22 mm in diameter.Although metastatic lung tumors were suspected,thoracoscopic lung biopsy led to the diagnosis of PLCH.At 6 months after he quit smoking,all nodules had almost disappeared.We investigated the characteristics of nodules at diagnosis in detail.Of 349 nodules in total,116 were in upper and 199 were in lower lobes.Ninety-six (27.5%) were cystic;the remaining 253 (72.5%) were non-cystic.The prevalence of cystic nodules was higher in upper lobes than in lower lobes (right upper 37.5% vs lower 18.2%,P = 0.0068;left upper 48.1% vs lower 24.4%,P = 0.0078).The average size (dia.) of cystic nodules was smaller than that of noncystic nodules (5.03 mm vs 7.40 mm,respectively,P < 0.0001).CONCLUSION Although multiple non-cystic nodules including large nodules (over 20 mm) are atypical,PLCH should be included in differential diagnoses.The presence of small cystic nodules predominantly in upper lobes and asymptomatic situation are also important for differential diagnoses to distinguish from metastatic cancers.
文摘Randomized controlled trials(RCTs) are the gold standard in terms of study design, however, in the surgical setting conducting RCTs can often be unethical or logistically impossible. Case-control studies should become the major study design used in surgical research when RCTs are unable to be conducted and definitely replacing case series which offer little insight into surgical outcomes and disease processes.
